I heard some places aren't open to tourists any more. One of the several examples being Kyoto's Gion district. Mainly because a small minority of idiots couldn't follow the simple rules like not snap pictures of unwilling people (and they felt harassed) and traipse on private property.

But in tourism it's also mixed with places that are just overcrowded these days or prices went through the roof and that's more a majority-problem. And then we have places where people had to put up fences and such because people were taking selfies right at the brittle cliff. And locals didn't want to scrape them off the ground. But that's not exactly "ruined" for other people. It's just that there is a fence now.